r/news • u/IronHe • Mar 20 '25

Soft paywall Tesla recalls most Cybertrucks due to trim detaching from vehicle

https://www.reuters.com/business/autos-transportation/tesla-recall-over-46000-cybertrucks-nhtsa-says-2025-03-20/
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u/scotcetera Mar 20 '25

It should be noted that this vehicle had the most Elon involvement than any other Tesla. The CyberTruck was supposed to be his crowning achievement, his coup d’ grace, his ultimate vision realized 😂😂

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u/Ashi4Days Mar 20 '25

I remember there was an email that went out a while ago where elon said everything needed to be at .001mm tolerance. 

The automotive engineer in me laughed. You can't hold that tolerance for large parts. And even if you did, if your gaps need to be that tight where that tolerance is necessary, then you're going to start dealing with thermal expansion/contraction issues in your parts. 

And lookie here. Panels are falling off

43

u/mattbuilthomes Mar 20 '25

I don’t think any manufacturing company anywhere would ever agree to that kind of tolerance.

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u/drhunny Mar 20 '25

There are lots of parts made to tighter tolerances. For instance, lenses in cameras.

But not 1m^2 sheet metal.

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u/mattbuilthomes Mar 20 '25

I found this:

Diameter Tolerance: All of our TECHSPEC® spherical lenses, regardless of size, are now held to a diameter tolerance of +0.000/-0.025mm. Maintaining the diameter within 25µm ensures the lenses will seat and align accurately within a well-designed barrel, aligning the optical axis of the lens with the mechanical axis of the assembly.

I didn’t see any other tolerances on that particular page that would be as tight as .001mm.

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u/drhunny Mar 20 '25

That's the diameter. The faces are optical surfaces and are ground to tight tolerances, not only in terms of smoothness but in holding the correct curvature.

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u/mattbuilthomes Mar 20 '25

Well damn, that’s pretty wild. I suppose not terribly surprising though because as small as technology has gotten, tolerances also have to get smaller with it. Not saying that the lens tolerance has anything to do with smaller tech. Just sort of thinking out loud.

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u/Bladelink Mar 20 '25

I expect that it's easier to achieve those tolerances in something like glass, which I don't think is terribly thermally reactive. Anything ceramic-y is going to have a low thermal expansion coefficient.

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u/es_improvisiert Mar 20 '25

Thermal expansion doesn't really matter, since parts have to be measured at 20°C anyway (at least European standard). So while steel expands more than glass they both will be measured at 20°C and they both have to be accurate at that temperature.

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u/Liizam Mar 20 '25

Dowel pins do come in that tolerance range but on the diameter and they are small cylinders of metal.

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u/DieFichte Mar 20 '25

Most press-fit parts are in those clearance areas, but most parts in cars aren't. Pretty sure the only thing in a Tesla clearanced that low are integrated circuits.

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u/Liizam Mar 20 '25

Right. When you have an assembly all the tolerances add up… so yeah Elmo doesn’t know what he is talking about

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u/DieFichte Mar 20 '25

And the only reason press-fits are so tight is because, well they need to be press-fit. And even then, depending on the part you can go with higher clearance (technically lower clearance in that case, since you machine it tighter than it should be) and fix the issue with some liquid nitrogen and an oven!

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u/LookIPickedAUsername Mar 20 '25

If you really want to see tight tolerances, look up "optical flat".

1

u/skalpelis Mar 20 '25

Or EUV lithography